This invention relates to gate valve actuators, and more particularly to hydraulically operated actuators for subsea well gate valves.
For some time the oil and gas industry has required hydraulic actuators for operating gate valves on subsea well christmas trees, pipe manifolds, and other underwater well apparatus, and such actuators of various designs are in widespread use for this purpose. Preferably, an actuator for this type of service would be capable of manual operation in the event of hydraulic power failure, would have provision for external adjustment to compensate for valve gate drift, could be manually operated and adjusted with readily available tools and minimal effort, and would be compact in size and functionally reliable.